Dental flask.



E. 0. PIBPER.

DENTAL FLASK.

APPLIGATION FILED JUNE 30, 1910.

7 1,068,698, Patented July 29, 1913.

WITNESSES IN VEN TOR ATTORNEY continued for about three minutes.

UTTED TAS PATNT @EFlfifi.

ERNEST O. PIEPER, OF SAN JOSE, CALIFORNIA.

DENTAL FLASK.

To all cuhom 2'25 may concern:

Be it known that I, ERNEST O. PIEPER, a citizen of the United States,residing at San Jose, in the county of Santa Clara and State ofCalifornia, have invented new and useful Improvements in Dental Flasks,of which the following is a specification.

This invention relates to improvements in dental flasks, the object ofthe invention being to provide a very simple form of flask, and yet onewhich is certain and etficient in operation.

In the accompanying drawing, Figure 1 is a perspective view of theflask; Fig. 2 is a vertical central section thereof.

Referring to the drawing, 1 indicates the cylindrical wall of myimproved flask having a base ring 2 to prevent tipping. Intermediate ofthe ends of said wall and formed integral therewith is an inwardlyextending dividing ring or diaphragm 3,

forming a central aperture 4.

In practising this invention, after mixing a sufficient quantity ofinvestment material, the upper part of the flask is filled about halffull, placing a finger in or under the hole 4 to retain the material insaid upper half. A crucible former is then inserted in the investmentmaterial to form a crucible 5. The flask is now inverted, still holdingthe crucible former in position, and the sprue 6, having thereon theimpression 7 or work to be reproduced, is inserted in the small hole inthe apex of the crucible former. The lower part of the flask con tainingthe impression or work to be reproduced is now filled with investmentmaterial, and the excess of material at the base is removed by a knifeto secure an even surface. The flask is set aside for about 15 minutes,and then the crucible former is removed by a entle rotary motion. Thematerial in the flask is then slowly dried out and when thoroughlydried, the sprue wire 6 is removed. By means of a very low flame, thewax impression is ab sorbed into the investment. The flask is now setupon an asbestos pad and the blow pipe is applied which will tend toburn out any wax that may not have been thus absorbed. The crucible isnow filled with pure gold of a quantity about twice that necessary toproduce the casting. The blow pipe is then applied in a large full flamethat will envelop the entire flask, and this process is TheSpecification of Letters Patent.

Application filed June 30, 1910.

Patented July 29, 1913.

Serial No. 569,758.

flame is then reduced and turned direct on the gold. When it isthoroughly melted a pressure or suction agent is employed and the moltengold is forced into the mold.

The novel feature of this invention is the dividing ring or diaphragm 3dividing the flask into two sections, which diaphragm prevents loss ofpressure or suction by escape of air between the wall of the flask andthe investment material when the latter are in a heated condition. Saiddiaphragm also prevents the pressure or suction being diminished bypassage of air through checks or cracks in the investment material,(which is always more or less porous,) and thus confines or restrictsthe pressure or suction to the crucible, so that the pressure or suctionis directed to the region of the sprue gate and directly over the mold.Said. ring or diaphragm is particularly advantageous in cases where themold is unusually large, extending almost to the wall of the flask, inwhich event, if the ring were not employed, the pressure fluid wouldpass down along the inner wall and enter the mold through the narrow intervening investment material between the mold and said wall, and,entering the mold in advance of the molten gold, would create acounterbalancing pressure within the mold, and thus prevent the goldfrom entering the mold. Moreover said dividing ring, when formedintegral with the wall, as shown in the drawing, serves as an additionalretaining wall for the investment, and is therefore especially useful incases of rapid or careless heating, which usually results in a blow-out,due to the generation of steam. The ring or diaphragm also preventscracks due to heat entering the lower or mold section from the upper orcrucible section. Said ring or diaphragm also serves as a medium forconducting the heat imparted to the wall of the flask to a point nearerthe center of investment than would otherwise be the case, thusaffording uniform heat distribution.

1. A dental flask having a surrounding wall formed in one piece and anannular flange extending inwardly from said wall at a suflicientdistance from one end of the flask to permit of a sprue gate beingformed in the flask at said end, and a suflicient distance from theother end to permit of a mold being formed within said wall at saidlatter end, said ring having an operatii e engagement with said Walladapted to pre vent the passage, between said wall and the inner edge ofsaid ring, of air of unequal pressures on opposite sides thereof.

2. A dental flask having a surrounding Wall formed in one piece, and aring or flange extending inwardly from said Wall mediate 0f the endsthereof, and having an 10 operative engagement with said wall adapted toprevent the passage between said Wall and diaphragm of air of unequalpressures on opposite sides thereof.

In testimony whereof I have hereunto set my hand in the presence of twosubscrib- 15 Copies of this patent may be obtained for five cents each,by addressing the Commissioner of Patents.

Washington, D. O.

